A system for communicating measurement data that performs a method of interrogating measurement signals from sensor means in a data carrier is known from the document EP0563713. The known system comprises a read/write station and at least one data carrier of the contactless type. The data carrier comprises an integrated circuit for logic operations and signal processing and a communication coil arrangement that is connected to the circuit. The communication coil arrangement is designed for the inductive coupling with a corresponding communication coil arrangement of the read/write station such that the circuit in the data carrier can be electrically powered and operated by means of a radio frequency signal that is generated and transmitted by the read/write station. The data carrier further comprises sensor means that are designed for sensing an environment parameter and for providing a sensor signal that represents the sensed environment parameter. In the prior art data carrier, the communication coil arrangement is connected to the circuit via antenna-connection pads. The sensor means are connected to the circuit via sensor-connection means that are different from the antenna-connection pads. The sensor means are powered via the circuit. In operation the known read/write station generates said radio frequency (RF) carrier signal that powers said data carrier and transmits a sensor data interrogation command to the data carrier. The circuit of the data carrier detects this command and interrogates said sensor signal from the sensor means and returns measurement data representing the sensor signal via the RF signal.
The known system suffers from the problem that sensor means must be either integrated with the circuit in order to utilize a semiconductor-based interface with the circuit, which integration is obviously relatively expensive and takes much semiconductor space, or the sensor means must be connected via additional connection pads to the circuit in the case of utilizing a conventional sensor located externally with regard to the circuit.